"Astrology includes many things, has many forms, and serves multiple purposes. Taking just three common examples, typical astrological charts show the positions and relations of the planets at the moment and location of birth. Progressed astrology maps the return of planets to their birth positions as well as the times and ways they cross and relate to those original positions and to one another. And horary astrology looks at the positions of the planets in the zodiac at a given moment when some decision is to be made (e.g., when to lay the foundation stone of a temple). And then there is the astrology once commonly found in newspapers, where planets were taken in conjunction with the signs of the zodiac to give general indications of what to expect for the day, given one’s birth sign. This latter was never taken seriously by knowledgeable astrologers, being rather like the sentiments found in fortune cookies ending meals in Chinese restaurants. "People admire your attitude," for example, can apply to anyone’s self-image, and so it "works." But such messages are random, and the newspaper’s astrological messages each have to be general enough to cover about 1/12 the population, because there are 12 signs in the zodiac.
There is much more to any system of astrology than the mechanisms for casting a chart or giving naïve interpretations, as, for example, Mars means conflict, Jupiter wealth or generosity, Mercury intelligence, and so on. Like all sciences, astrology is a complex of symbols and principles of interrelationships. And like all science, astrology is also based on experience and observation. In some ways, astrology is more like medical science than physics, since its variables are often multivalent and context-dependent. And like all sciences, astrology is based on assumptions about the nature of reality and the universe. It shares with all sciences the assumption that there are discoverable laws of nature that are invariant, at least over long periods of time. It shares the assumption that nature and the universe is intelligible to a reasoning, observing consciousness.
Astrology comes in many forms. Traditional astrology maps the planets as if the earth were the center of the universe. Solar astrology places the sun in the center. Western astrology traditionally fixes the twelve signs of the zodiac as if the sun enters Aries each spring equinox, but the slight, slow wobble of the earth in its orbit, rather like a spinning top rotates its upper part in a circle, precesses the equinoxes in a cycle of over 25,000 years. This means that over time the sun appears in different signs at the spring equinox. This is the idea behind the Age of Aquarius, emerging after approximately 2500 years of the Age of Pisces, Aries ending about 2500 years ago when the Piscean Age began. Indian astrology calculates this precession of the equinoxes and so places the sun now in or near Aquarius (depending on the method of calculation). So the zodiac fixed in the calendar of Western astrology is one sign off by Indian standards. Since astrology has theoretical and symbolic content as well as empirical content, those born under a particular sign as measured in Western astrology would be considered to have been born under a sign one place earlier in the precessed zodiacal system of Indian astrology. This will show up in the fact that many people find characteristics of the previous sign as applying to themselves as well as the characteristics of their Western birth sign, since some features are established by empirical experience and other by theoretical considerations."